Amazon Pinpoint - Custom Channel Lambda function (Node.js)

index.js

const https = require("https");

/* FB configuration */
const FB_ACCESS_TOKEN = "EAF...DZD";
const FB_PSID = "facebookMessengerPsid";
const FB_REQUEST = {
    host: "graph.facebook.com",
    path: "/v2.6/me/messages?access_token=" + FB_ACCESS_TOKEN,
    method: "POST",
    headers: {
        "Content-Type": "application/json",
    },
};


const isFBActive = (user) =>
    user &&
    user.UserAttributes &&
    user.UserAttributes[FB_PSID]


exports.handler = async (event, context) => {
    const messagesToSend = [];

    if (event.Message && event.Endpoints) {
        for(const [id, endpoint] of Object.entries(event.Endpoints)) {
            if (isFBActive(endpoint.User)) {
                messagesToSend.push(deliver(event.Message, endpoint.User));
            }
        }
    }

    await Promise.all(messagesToSend);

    return {
        body: "ok",
        statusCode: 200,
    };
};


const deliver = (message, user) => {
    console.log("Sending message for user: ", user.UserId);

    const requestBody = JSON.stringify({
        recipient: {
            id: user.UserAttributes[FB_PSID][0],
        },
        message: {
            text: message["smsmessage"]["body"],
        },
    });

    return new Promise((resolve, reject) => {
        const req = https.request(FB_REQUEST, (response) => {
            let responseBody = '';
            response.on('data', chunk => {
                responseBody += chunk;
            });
            response.on('end', () => {
                resolve(responseBody);
            });
            response.on('error', (error) => {
				reject(error);
			});
            response.resume(); 
        });
        req.write(requestBody);
        req.end();
    });
};